Experiments are reported on directions of influence in mother-infant interaction. Seemingly responsive but incidental behaviors attributed to each mother's own infant (vocalizations in Experiment 1, headturns toward mother in Experiment 2) were found, in Experiment 1, to condition each mother's verbal phrases accompanying her smiles and, in Experiment 2, to condition each mother's smiles or other facial expressions. In Experiment 3, the rapidity of the infant's headturn that followed the mother's response of displaying a particular toy was found to condition that maternal response.